1. Field of the Invention
The present invention relates to a washing machine, and, more particularly, to a washing machine having a motor disposed inside a tub, whereby washing capacity of the washing machine is greatly increased.
2. Description of the Related Art
FIG. 1 is a side view, in section, showing a conventional washing machine.
As shown in FIG. 1, the conventional washing machine comprises: a cabinet 2 forming the external appearance of the washing machine, the cabinet 2 having a laundry inlet/outlet hole formed at the front surface thereof for allowing laundry m to be put into or removed from the cabinet 2; a door 4 hingedly mounted at the front surface of the cabinet 2 for opening and closing the laundry inlet/outlet hole; a tub 6 mounted in the cabinet 2 in a shock absorbing fashion; a water supply unit 10 for supplying detergent or wash water w into the tub 6; a water draining unit 12 for draining the wash water w in the tub 6 out of the cabinet 2; a drum 20 rotatably disposed in the tub 6 for receiving the laundry m; and a motor 30 for rotating the drum 20.
The tub 6 has an opening hole 7, which is disposed at the rear of the laundry inlet/outlet hole of the cabinet 2 such that the laundry m can be put into or removed from the drum 20. Through the center of the rear surface of the tub 6 is inserted a drive shaft 32 of the motor 30.
The drum 20 has an opening hole 7, which is also disposed at the rear of the laundry inlet/outlet hole of the cabinet 2 such that the laundry m can be put into or removed from the drum 20. The drum 20 is disposed such that the lower part of the drum 20 is submerged in the wash water received in the tub 6. The drum 20 is provided at the circumferential surface and the rear surface thereof with a plurality of through-holes 22.
At the inner circumferential surface of the drum 20 are mounted lifters 26 for lifting the laundry m received in the drum 20 to the inner upper part of the drum 20 such that the lifted laundry m falls due to gravity.
At the rear surface of the drum 20 is mounted a spider 28, to which the drive shaft 32 of the motor 30 is securely connected.
The motor 30 is mounted at the rear of the tub 6. The motor 30 is horizontally or nearly horizontally disposed such that the drive shaft 32 is connected to the center of the rear surface of the drum 20 through the center of the rear surface of the tub 6.
The motor 30 comprises: the above-described drive shaft 32; a motor frame 36 fixed to the rear surface of the tub 6, the motor frame 36 having a through-hole, through which the drive shaft 32 is inserted; a stator 40 fixed to the motor frame 36; and a rotor 44 fixed to the drive shaft 32 for performing rotation by an electromagnetic force generated between the stator 40 and the rotor 44.
The drive shaft 32 has one end fixed to the spider 28 of the drum 20 and the other end protruding toward the rear of the tub 6 such that the drive shaft 32 is inserted through the tub 6 and the motor frame 36.
The motor frame 36 is bent such that the edge of the motor frame 36 protrudes in the circumferential direction, and the motor frame 36 is fixed to the rear surface of the tub by means of fixing bolts 37.
The stator 40 is formed in the shape of a hollow cylinder. The stator 40 is fixed to the rear surface of the motor frame 36 by means of fixing bolts 41b. 
The rotor 44 comprises: a cup-shaped rotor frame 45; and a magnet 46 fixed to the inner circumferential surface of the rotor frame 45 while being spaced apart from the stator 36.
Unexamined reference numeral 49 indicates a gasket disposed between the laundry inlet/outlet hole of the cabinet 2 and the opening hole 7 of the tub 6.
Now, the operation of the conventional washing machine with the above-stated construction will be described.
When a user puts laundry m into the drum 20, closes the door 4, and operates the washing machine, wash water w containing detergent dissolved therein, which is supplied from the water supply unit 10, is gathered in the inner lower part of the tub 6, the lower part of the drum 20 is submerged in the wash water w containing detergent dissolved therein, and the laundry m received in the drum 20 is wetted by the wash water w containing detergent dissolved therein, which is introduced into the drum 20 through the through-holes 22 of the drum 20.
When electric voltage is applied to a coil 43 of the motor 30, an electromagnetic force is generated between the coil 43 and the magnet 46, and therefore, the magnet 46 is rotated. The rotating force of the magnet 46 is transmitted to the drive shaft 32 through the rotor frame 45, and the drum 20 is rotated by the drive shaft 32.
While the drum 20 is rotated, the laundry m is lifted by the lifters 26, and then falls from the lifters 26. At this time, contaminants are separated from the laundry m by the actions of the detergent and the wash water w. After the above-described washing operation is completed, the contaminated wash water in the tub 6 is drained out of the washing machine through the water draining unit 12.
Subsequently, clean water w containing no detergent is supplied to the tub 6 through the water supply unit 10. When electric voltage is applied to the coil 43 of the motor 30 as in the washing operation, the drum 20 is rotated by the drive shaft 32. As a result, the laundry m is lifted by the lifters 26, and then falls from the lifters 26. At this time, bubbles are removed from the laundry m, and the contaminated water is drained out of the washing machine through the water draining unit 12.
Thereafter, electric voltage, which is higher than that used in the washing operation or the rinsing operation, is applied to the coil 43 of the motor 30, and therefore, the drum 20 is rotated at high speed by the drive shaft 32. As a result, moisture is centrifugally separated from the laundry m. The separated moisture is collected in the tub 6 through the through-holes 22 of the drum 20, and is then drained out of the washing machine through the water draining unit 12.
In the conventional washing machine with the above-stated construction and operation, however, the motor 30 is mounted outside the tub 20 at the rear of the tub 20. As a result, washing capacity of the washing machine is decreased, and vibration and noise generated from the motor are increased. Furthermore, the rotor 44 may collide with the cabinet 2, and therefore, noise due to the collision may be generated. In addition, safety of the washing machine is lowered.